Soya isoflavones are compounds with phytoestrogenic characteristics,
i.e. because of their structure, their effects are similar to those of animal
estrogens. This is why they are used for medicinal purposes in aging women.
The presented experiment with laying hens was conducted to demonstrate the
possibility of transferring soya isoflavones from feed into egg yolk to produce
isoflavone-enriched eggs. Laying hens were randomly assigned to a control
and 3 experimental groups and fed a basal diet or the basal diet supplemented
with different concentrations of isoflavones: 1000, 2000 or 3000 mg · kg–1 feed.
The transfer of isoflavones (daidzein and genistein) from the feed into the egg
yolk of treated hens was found to be significant. At the end of the experiment,
the content of the analysed isoflavones was from 396.0 to 412.4 μg.

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